/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.jasper.compiler;

import org.apache.tomcat.JarScanner;
import org.apache.tomcat.util.scan.StandardJarScanner;

import javax.servlet.ServletContext;

/**
 * Provide a mechanism for Jasper to obtain a reference to the JarScanner
 * implementation.
 */
public class JarScannerFactory {

	private JarScannerFactory() {
		// Don't want any instances so hide the default constructor.
	}

	/**
	 * Obtain the {@link JarScanner} associated with the specified {@link
	 * ServletContext}. It is obtained via a context parameter.
	 */
	public static JarScanner getJarScanner(ServletContext ctxt) {
		JarScanner jarScanner =
				(JarScanner) ctxt.getAttribute(JarScanner.class.getName());
		if (jarScanner == null) {
			ctxt.log(Localizer.getMessage("jsp.warning.noJarScanner"));
			jarScanner = new StandardJarScanner();
		}
		return jarScanner;
	}

}
